Merge pull request #2635 from retronym/ticket/7151

SI-7151 Emit final in bytecode for final inner classes.

src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala

@@ -415,7 +415,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM {
 
     val INNER_CLASSES_FLAGS =
       (asm.Opcodes.ACC_PUBLIC    | asm.Opcodes.ACC_PRIVATE | asm.Opcodes.ACC_PROTECTED |
-       asm.Opcodes.ACC_STATIC    | asm.Opcodes.ACC_INTERFACE | asm.Opcodes.ACC_ABSTRACT)
+       asm.Opcodes.ACC_STATIC    | asm.Opcodes.ACC_INTERFACE | asm.Opcodes.ACC_ABSTRACT | asm.Opcodes.ACC_FINAL)
 
     // -----------------------------------------------------------------------------------------
     // factory methods
@@ -648,11 +648,12 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM {
 
         // sort them so inner classes succeed their enclosing class to satisfy the Eclipse Java compiler
         for (innerSym <- allInners sortBy (_.name.length)) { // TODO why not sortBy (_.name.toString()) ??
-          val flags = mkFlags(
+          val flagsWithFinal: Int = mkFlags(
             if (innerSym.rawowner.hasModuleFlag) asm.Opcodes.ACC_STATIC else 0,
             javaFlags(innerSym),
             if(isDeprecated(innerSym)) asm.Opcodes.ACC_DEPRECATED else 0 // ASM pseudo-access flag
           ) & (INNER_CLASSES_FLAGS | asm.Opcodes.ACC_DEPRECATED)
+          val flags = if (innerSym.isModuleClass) flagsWithFinal & ~asm.Opcodes.ACC_FINAL else flagsWithFinal // For SI-5676, object overriding.
           val jname = javaName(innerSym)  // never null
           val oname = outerName(innerSym) // null when method-enclosed
           val iname = innerName(innerSym) // null for anonymous inner class

test/files/run/t7151.check

@@ -0,0 +1,6 @@
+class Test$InnerObject$ isFinal = false
+class Test$InnerCase isFinal = true
+class Test$InnerNonCase isFinal = true
+class TopLevelObject$ isFinal = true
+class TopLevelCase isFinal = true
+class TopLevelNonCase isFinal = true

test/files/run/t7151.scala

@@ -0,0 +1,24 @@
+import java.lang.reflect.Modifier.isFinal
+
+object Test {
+  object InnerObject
+  final case class InnerCase()
+  final class InnerNonCase()
+
+  def main(args: Array[String]) {
+    def checkFinal(clazz: Class[_]) =
+      println(s"${clazz} isFinal = ${isFinal(clazz.getModifiers())}")
+
+    checkFinal(InnerObject.getClass)
+    checkFinal(classOf[InnerCase])
+    checkFinal(classOf[InnerNonCase])
+
+    checkFinal(TopLevelObject.getClass)
+    checkFinal(classOf[TopLevelCase])
+    checkFinal(classOf[TopLevelNonCase])
+  }
+}
+
+object TopLevelObject
+final case class TopLevelCase()
+final case class TopLevelNonCase()